A variety of herbicidal compositions are known to be useful for controlling weeds in crops of cultivated plants. When applying herbicides to control weeds, the cultivated plants can also suffer damage owing to factors including, but are not limited to, the concentration of the herbicide(s), the mode of application, the cultivated plant itself, the nature of the soil, and the climatic conditions such as exposure to light, temperature and rainfall. To counteract this problem, one or more safeners, which are able to antagonise the harmful action of the herbicide(s) on the cultivated plant, are traditionally included in the herbicidal compositions so as to protect the cultivated plant while leaving the herbicidal action on the weeds to be controlled virtually unimpaired.
However, it has been found that many safeners often have a very specific action with respect not only to the cultivated plants but also to the herbicide, and in some cases also subject to the mode of application, i.e., a specific safener will often be suitable only for a specific cultivated plant and a specific class of herbicides or a specific herbicide. For example, it has been found that the safeners cloquintocet or cloquintocet-mexyl and mefenpyr or mefenpyr-diethyl, which are known from EP-A-0 191 736 (e.g., compound 1.316) and WO 91/07874 (e.g., Example 3), can indeed protect cultivated plants from the phytotoxic action of, in particular, 3-hydroxy-4-(4-methylphenyl)-5-oxo-pyrazoline derivatives, but partly attenuate the herbicidal action on weeds.
Given the specific action of safeners, it would be beneficial if herbicidal compositions could be formulated, without the need of a safener, and still provide a broader spectrum of weed control in crops of cultivated plants while providing relatively low levels of phytotoxicity to the cultivated plants to which the herbicidal composition is applied.
What is needed in the art is the development of herbicidal compositions that provide a broader spectrum of weed control while also reducing or maintaining acceptable levels of phytotoxicity to useful cultivated plants to which the herbicidal composition is applied, without the need for a safener in the herbicidal composition.